1. Field of the Invention
The invention relates to a battery pack module, more particularly to a rechargeable battery pack module for a portable computer.
2. Description of the Related Art
In this age of rapid technological advancement, computers have become indispensable tools in our daily lives. Because of different needs, computers have evolved from a desktop form to a lighter and more compact form for enhanced portability such that use of the computer is no longer limited to the vicinity of a computer table. When using a portable computer outdoors, a rechargeable battery pack module is needed to supply electrical power to operate the computer. Currently, manufacturers continue to perform research in connection with increasing the power capacity of battery pack modules and with making the battery pack modules more environmental friendly. Present nickel-hydrogen (NiH) battery pack modules are now being replaced with lithium-ion (Li-ion) battery pack modules. While the power supplying capacity of conventional lithium-ion battery pack modules can satisfy the requirements of most users, it is noted that the fixed current or fixed voltage recharging schemes which are currently available are still unsatisfactory in terms of the charging time and safety features during charging. There is still much room for improvement of the charging circuit of lithium-ion battery pack modules.
It is noted that conventional lithium-ion battery pack modules are integrated into portable computers and are not designed to be detachable therefrom. The conventional lithium-ion battery pack module relies upon the internal circuitry of the portable computer and upon software routines for recharging the same. For example, the lithium-ion battery pack module can be recharged under a slow charge mode or a fast charge mode. In the slow charge mode, a smaller charging current is supplied to the battery pack module while the computer is in use. In the fast charge mode, a larger charging current is supplied to the battery pack module while the computer is not in use. Regardless of the mode under which the battery pack module is charged, charging of the battery pack module has to be conducted internally of the portable computer, thereby resulting in inconvenience. Moreover, the conventional charging circuit of lithium-ion battery pack modules is unable to detect for the presence of abnormalities in the temperature of the battery pack module during charging. This can arise in a dangerous situation in the event of excessively high temperatures during charging. In addition, conventional battery pack modules are unable to indicate manufacturer information relevant thereto, such as the brand of lithium cells that are in use, the manufacturing date of the lithium cells, etc.